Many operating systems, such as the MS-DOS, version 5, operating system, sold by Microsoft Corporation of Redmond, Washington, support only short filenames. In the MS-DOS, version 5, operating system, filenames may be a maximum length of eleven characters. Each filename may have a main portion of eight characters followed by an extension of three characters. An example filename in the MS-DOS, version 5, operating system is "EXAMPLE1. EXE", wherein "EXAMPLE1" constitutes the main portion and "EXE" constitutes the extension.
Each filename is limited to eleven characters due to constraints in the file system of the MS-DOS, version 5, operating system. This file system employs a directory structure in which each file has a directory entry associated with it. Unfortunately, the directory entry for a file only supports filenames with a maximum length of eleven characters. Such a limit in the length of the filenames is often frustrating to a user. The length limit of eleven characters prevents a user from employing adequately descriptive filenames and, in many instances, forces a user to insert awkward abbreviations of descriptive terms into the filename.